docs: def save_otfs(
          self,
          ufos,
          ttf=False,
          is_instance=False,
          interpolatable=False,
          use_afdko=False,
          autohint=None,
          subset=None,
          use_production_names=None,
          subroutinize=None,  # deprecated
          optimize_cff=CFFOptimization.NONE,
          cff_round_tolerance=None,
          remove_overlaps=True,
          overlaps_backend=None,
          reverse_direction=True,
          conversion_error=None,
          feature_writers=None,
          interpolate_layout_from=None,
          interpolate_layout_dir=None,
          output_path=None,
          output_dir=None,
          inplace=True,
      ):
          """Build OpenType binaries from UFOs.
  
          Args:
              ufos: Font objects to compile.
              ttf: If True, build fonts with TrueType outlines and .ttf extension.
              is_instance: If output fonts are instances, for generating paths.
              interpolatable: If output is interpolatable, for generating paths.
              use_afdko: If True, use AFDKO to compile feature source.
              autohint: Parameters to provide to ttfautohint. If not provided, the
                  autohinting step is skipped.
              subset: Whether to subset the output according to data in the UFOs.
                  If not provided, also determined by flags in the UFOs.
              use_production_names: Whether to use production glyph names in the
                  output. If not provided, determined by flags in the UFOs.
              subroutinize: If True, subroutinize CFF outlines in output.
              cff_round_tolerance (float): controls the rounding of point
                  coordinates in CFF table. It is defined as the maximum absolute
                  difference between the original float and the rounded integer
                  value. By default, all floats are rounded to integer (tolerance
                  0.5); a value of 0 completely disables rounding; values in
                  between only round floats which are close to their integral
                  part within the tolerated range. Ignored if ttf=True.
              remove_overlaps: If True, remove overlaps in glyph shapes.
              overlaps_backend: name of the library to remove overlaps. Can be
                  either "booleanOperations" (default) or "pathops".
              reverse_direction: If True, reverse contour directions when
                  compiling TrueType outlines.
              conversion_error: Error to allow when converting cubic CFF contours
                  to quadratic TrueType contours.
              feature_writers: list of ufo2ft-compatible feature writer classes
                  or pre-initialized objects that are passed on to ufo2ft
                  feature compiler to generate automatic feature code. The
                  default value (None) means that ufo2ft will use its built-in
                  default feature writers (for kern, mark, mkmk, etc.). An empty
                  list ([]) will skip any automatic feature generation.
              interpolate_layout_from: A DesignSpaceDocument object to give varLib
                  for interpolating layout tables to use in output.
              interpolate_layout_dir: Directory containing the compiled master
                  fonts to use for interpolating binary layout tables.
              output_path: output font file path. Only works when the input
                  'ufos' list contains a single font.
              output_dir: directory where to save output files. Mutually
                  exclusive with 'output_path' argument.
          """
          assert not (output_path and output_dir), "mutually exclusive args"
  
          if output_path is not None and len(ufos) > 1:
              raise ValueError("output_path requires a single input")
  
          if subroutinize is not None:
              import warnings
  
              warnings.warn(
                  "the 'subroutinize' argument is deprecated, use 'optimize_cff'",
                  UserWarning,
              )
              if subroutinize:
                  optimize_cff = CFFOptimization.SUBROUTINIZE
              else:
                  # for b/w compatibility, we still run the charstring specializer
                  # even when --no-subroutinize is used. Use the new --optimize-cff
                  # option to disable both specilization and subroutinization
                  optimize_cff = CFFOptimization.SPECIALIZE
  
          ext = "ttf" if ttf else "otf"
  
          if interpolate_layout_from is not None:
              if interpolate_layout_dir is None:
                  interpolate_layout_dir = self._output_dir(
                      ext, is_instance=False, interpolatable=interpolatable
                  )
              finder = partial(_varLib_finder, directory=interpolate_layout_dir, ext=ext)
              # no need to generate automatic features in ufo2ft, since here we
              # are interpolating precompiled GPOS table with fontTools.varLib.
              # An empty 'featureWriters' list tells ufo2ft to not generate any
              # automatic features.
              # TODO: Add an argument to ufo2ft.compileOTF/compileTTF to
              # completely skip compiling features into OTL tables
              feature_writers = []
  
          compiler_options = dict(
              useProductionNames=use_production_names,
              reverseDirection=reverse_direction,
              cubicConversionError=conversion_error,
              featureWriters=feature_writers,
              inplace=True,  # avoid extra copy
          )
          if use_afdko:
              compiler_options["featureCompilerClass"] = FDKFeatureCompiler
  
          if interpolatable:
              if not ttf:
                  raise NotImplementedError("interpolatable CFF not supported yet")
  
              logger.info("Building interpolation-compatible TTFs")
  
              fonts = ufo2ft.compileInterpolatableTTFs(ufos, **compiler_options)
          else:
              fonts = self._iter_compile(
                  ufos,
                  ttf,
                  removeOverlaps=remove_overlaps,
                  overlapsBackend=overlaps_backend,
                  optimizeCFF=optimize_cff,
                  roundTolerance=cff_round_tolerance,
                  **compiler_options
              )
  
          do_autohint = ttf and autohint is not None
  
          for font, ufo in zip(fonts, ufos):
  
              if interpolate_layout_from is not None:
                  master_locations, instance_locations = self._designspace_locations(
                      interpolate_layout_from
                  )
                  loc = instance_locations[_normpath(ufo.path)]
                  gpos_src = interpolate_layout(
                      interpolate_layout_from, loc, finder, mapped=True
                  )
                  font["GPOS"] = gpos_src["GPOS"]
                  gsub_src = TTFont(finder(self._closest_location(master_locations, loc)))
                  if "GDEF" in gsub_src:
                      font["GDEF"] = gsub_src["GDEF"]
                  if "GSUB" in gsub_src:
                      font["GSUB"] = gsub_src["GSUB"]
  
              if do_autohint:
                  # if we are autohinting, we save the unhinted font to a
                  # temporary path, and the hinted one to the final destination
                  fd, otf_path = tempfile.mkstemp("." + ext)
                  os.close(fd)
              elif output_path is None:
                  otf_path = self._output_path(
                      ufo, ext, is_instance, interpolatable, output_dir=output_dir
                  )
              else:
                  otf_path = output_path
  
              logger.info("Saving %s", otf_path)
              font.save(otf_path)
  
              # 'subset' is an Optional[bool], can be None, True or False.
              # When False, we never subset; when True, we always do; when
              # None (default), we check the presence of custom parameters
              if subset is False:
                  pass
              elif subset is True or (
                  (KEEP_GLYPHS_OLD_KEY in ufo.lib or KEEP_GLYPHS_NEW_KEY in ufo.lib)
                  or any(glyph.lib.get(GLYPH_EXPORT_KEY, True) is False for glyph in ufo)
              ):
                  self.subset_otf_from_ufo(otf_path, ufo)
  
              if not do_autohint:
                  continue
  
              if output_path is not None:
                  hinted_otf_path = output_path
              else:
                  hinted_otf_path = self._output_path(
                      ufo,
                      ext,
                      is_instance,
                      interpolatable,
                      autohinted=True,
                      output_dir=output_dir,
                  )
              try:
                  ttfautohint(otf_path, hinted_otf_path, args=autohint)
              except TTFAError:
                  # copy unhinted font to destination before re-raising error
                  shutil.copyfile(otf_path, hinted_otf_path)
                  raise
              finally:
                  # must clean up temp file
                  os.remove(otf_path)